1

I'm trying to sort a 10X15 array of characters, where each row is a word. My goal is to sort it in a descending order, from the largest value word at the top, at array[row 0][column 0 through 14] position, and the smallest value word at the bottom array[row 9][column 0 through 14]. Each row is a word (yeah, they don't look as words, but it's to test the sorting capability of the program).

To clarify: What I need to do is this... considering that EACH row is a whole word, I need to sort the rows from the highest value word being at the top, and the lowest value word being at the bottom.

Edit:

Everything works now. For anyone who has a similar question, look to the comments below, there are several fantastic solutions, I just went with the one where I create my own sort function to learn more about sorting. And thanks to all of you for helping me! :)

Improve this question
8
  • Your description of the problem seems contradictory. It's not clear to me whether you want to sort the individual rows, the rows by the first letter, both, or all letters, mixing letters from different 'words'. Commented Feb 8, 2013 at 0:54
  • 3
    Convert each row into a string, add the string to a vector, once all the strings have been added, sort the vector, then write the strings back out to the array. Commented Feb 8, 2013 at 0:55
  • @us2012 I need to sort the words, each row is a word. But there are words that are almost the same, up until like the last letter in them. So obviously each letter (otherwise known as a column) has to be compared. Commented Feb 8, 2013 at 0:59
  • Are you writing your own sorting algorithm or can you use std::sort? And what do you mean by "highest value" and "lowest value"? Are you sorting in dictionary order? Commented Feb 8, 2013 at 1:04
  • It's better if I create my own. But at the end of the day it'll come down to even getting this to work. Commented Feb 8, 2013 at 1:09

3 Answers 3

Reset to default
2

You are using c++ so quit using arrays and begin with stl types:

Convert each row into a string:

string tempString
for (int i = 0; i < rowSize; ++i) {
    tempString.pushBack(array[foreachrow][i])
}

add them to a vector

std::vector<std::string> sorter;
sorter.push_back(tempString);

Do that for each row. 

std::vector<std::string> sorter;
for each row {
    for each coloumn {
        the string thing

    }
    push back the string
}

Then sort the vector with std::sort and write the vector back into the array (if you have to but don't because arrays suck)

Improve this answer
Sign up to request clarification or add additional context in comments.

12 Comments

Yeah....... the problem requires me to use 10x15 array of characters. So not like it's my choice. Looking over your solution right now. :)
are you not allowed to import std::libs? because you can use stl containers then ouput as an array.
I'm allowed to do whatever I wish. But it has to be simple enough for a beginning C++ class. The only requirements are that I have a 10x15 array of characters, in which each row is a word; I have to have a sorting function and a printing function. That's it. Also, it's telling me that string doesn't have .pushBack...
@Noobacode this is pretty clearly pseudo code. I am not going to write your homework for you. You will need to figure out the way to make the for loop do what you want. and yes, it is push_back().
@Noobacode you dont have to write your own sorting function: cplusplus.com/reference/algorithm/sort std::sort will do it for you.
|
2

As usual, you need qsort:

void qsort( const void *ptr, size_t count, size_t size,
            int (*comp)(const void *, const void *) );

That takes a void pointer to your starting address, the number of elements to sort, the size of each element, and a comparison function.

You would call it like this:

qsort( array, ROWS, COLS, compare_word );

Where you define compare_word to sort in reverse:

int compare_word( const void* a, const void* b )
{
    return strncmp( b, a, COLS );
}

Now, given that each word is 15 characters long, there may be padding to deal with. I don't have absolute knowledge that the array will be packed as 10 by 15 instead of 10 by 16. But if you suspect so, you could pass (&array[1][0] - &array[0][0]) as the element size instead of COLS.

If you are not allowed to use qsort and instead must write your own sorting algorithm, do something simple like selection sort. You can use strncmp to test the strings. Look up the function (google makes it easy, or if you use Linux, man 3 strncmp). To swap the characters, you could use a temporary char array of length COLS and then 3 calls to memcpy to swap the words.

Improve this answer

1 Comment

I'm trying to use string.compare on my vector values right now using bubble sort, but it's not working out well (see original post).
2

The problem with your new code using string and vector is a simple typo:

sorter[count] = array[count+1]; should be sorter[count] = sorter[count+1];

Improve this answer

3 Comments

any ideas on why my vector to array conversion is not working in convArray()?
@Noobacode Same typo as the other one, only the other way round - sorter[row][col]=tempString[col]; should be array[row][col]=tempString[col];.
Duh... oh my, I guess that's what all day in front of a computer does to you. Thank you so much sir!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.